Communication system for multizone irrigation

ABSTRACT

A multizone irrigation system includes a central control unit having a central control system interfaced with a central valve and a central communication unit. The central valve regulates water flow for irrigation from a water source and can lower water pressure in the pipes at its output. The central communication unit is constructed to transmit or receive pressure based communication signals providing irrigation information. Each zone includes a sprinkler control unit having a sprinkler connected to a water pipe for irrigation. Each sprinkler control unit includes a local controller interfaced with a local valve for controlling water flow to the sprinkler. The sprinkler control unit also includes a local communication unit (e.g., a pressure sensor) constructed to receive communication signals from the central communication unit and provide received irrigation information to the local controller.

This application is a divisional of U.S. application Ser. No.11/318,254, filed on Dec. 23, 2005, now U.S. Pat. No. 7,383,721, whichis a continuation application of PCT application PCT/US2004/020504,filed on Jun. 24, 2004, entitled “Communication System for MultizoneIrrigation,” which is a continuation-in-part of PCT applicationPCT/US2003/020117, filed on Jun. 24, 2003, entitled “Automatic WaterDelivery Systems with Feedback Control,” which claims priority from U.S.Provisional Applications 60/391,282 and 60/391,284 both filed on Jun.24, 2002, all of which are incorporated by reference. The PCTapplication PCT/US2004/020504 is also a continuation-in part ofPCT/US2002/38757, filed on Dec. 4, 2002, and is a continuation-in-partof PCT/US02/38758, both filed on Dec. 4, 2002, which are incorporated byreference.

BACKGROUND OF THE INVENTION

The present invention relates to communications systems and methods forautomated irrigation systems, which provide central and local control ofdelivered amounts of water.

There are various sprinkler devices for watering gardens, yards, or foragricultural uses. These devices may have a controller installed at asource of pressurized water and a remotely located sprinkler. Thesprinklers include a rotatable water guide with a water nozzle. Whenwater is ejected from the nozzle, it flows initially through the waterguide piece that rotates over a full circle or over a semicircularpattern. The spraying speed is frequently determined by the water flowspeed. That is, the water speed governs the rotation of the water guidepiece and thus the irrigation pattern.

Many irrigation controllers are time based. The water delivery isactivated over a selected period of time regardless of the temperature,air humidity, soil moisture or other vegetation growth factors.Furthermore, the water delivery may vary with the water source pressureand other factors.

Therefore, there is still a need for reliable water delivery systems andcontrol methods capable of delivering selected or known amounts ofwater. There is still also a need for automated water delivery systemsand methods that enable a local loop feedback control and/or can detectlocal malfunctions.

SUMMARY OF THE INVENTION

The present invention relates to communication systems and methods forautomated irrigation systems installed in-ground or above-ground. Theautomated irrigation systems control and meter the amounts of waterdelivered from one or several irrigation zones.

One type of the communication system is used for selectively controllingmultiple zones and delivering a selectable water amount (or irrigatingdifferent amounts of water from the individual zones) according to thelocal irrigation needs. A multizone irrigation system includes a centralcontrol unit having a central controller-interfaced with a central valveand a central communication unit. The central valve regulates water flowfor irrigation from a water source. The central communication unit isconstructed to transmit or receive communication signals providingirrigation information. Each zone includes a sprinkler control unitincluding a sprinkler connected to a water pipe for irrigation of a landarea. The sprinkler control unit includes a local controller interfacedwith a local valve for controlling water flow to the sprinkler. Thesprinkler control unit also includes a local communication unitconstructed to receive communication signals from the centralcommunication unit and provide received irrigation information to thelocal controller. In a bi-directional system, one or several localcommunication units are constructed to transmit communication signals tothe central communication unit which provide received information to thecentral controller. The central controller thus can store specificirrigation cycles including the water amounts delivered by eachsprinkler or each zone. The local controller controls operation of thelocal valve based on the irrigation information received from thecentral controller and information provided by the individual localsensors.

According to one embodiment, a communication system used in anirrigation system includes a central controller interfaced with acentral valve and a central communication unit, and a number ofsprinkler units each unit including a local controller interfaced with alocal valve for controlling water flow to a sprinkler, and a localcommunication unit. The central valve regulates water flow forirrigation from a water source. The central communication unit isconstructed to transmit communication signals providing irrigationinformation. The sprinkler units are constructed to irrigate a landarea. The local communication unit is constructed to receivecommunication signals from the central communication unit, and providereceived irrigation information to the local controller. The localcontroller is constructed to control operation of the local valve basedon the irrigation information.

The central communication unit is constructed to receive thecommunication signals, and the local communication unit is constructedto transmit communication signals.

The central communication unit and the local communication unit arecoupled to water conduits connected to the water source and areconstructed to generate pressure waves transmitted through water in theconduits. The central communication unit and the local communicationunit include a pressure sensor arranged to detect the pressure waves.

The central communication unit and the local communication unit arecoupled to water conduits connected to the water source and areconstructed to generate pressure pulses or ultrasound waves transmittedthrough water in the conduits.

Furthermore, the automated systems and methods enable water deliverybased on a local loop feedback control and/or control of a deliveredamount of water at different water pressures. These systems can be usedfor watering lawns, gardens, yards, golf courses, or for agriculturaluses.

According to yet another embodiment, a remotely located irrigationsystem includes a controller connected to receive data from a sensor,and a valve device including an actuator. The system has a water inputport constructed to be coupled to a water conduit receiving water from aremotely located water source. The controller is located near the waterinput port and provides control signals to the actuator. The actuatorinitiates the on and off states of the valve device located near, andconnected to, the water input port for providing water to a waterdelivery device such as a sprinkler or a drip irrigation device.

According to yet another aspect, an irrigation system includes a waterinput port constructed receiving water from a remotely located watersource, and a controller located near the water input port and connectedto at least one sensor. The system also includes a valve deviceincluding an actuator located near and connected to the water inputport, wherein the valve device is constructed to receive control signalsfrom the controller for providing water to a sprinkler.

Preferred embodiments may include one or more of the following features:The controller may be battery operated. The actuator is a latchingactuator (as described in U.S. Pat. No. 6,293,516, which is incorporatedby reference), a non-latching actuator (as described in U.S. Pat. No.6,305,662, which is incorporated by reference), or an isolated operator(as described in PCT Application PCT/US01/51098, which is incorporatedby reference).

The sensor may be a precipitation sensor, humidity sensor, a soilmoisture sensor, or a temperature sensor.

The remotely located irrigation system may include an indicatorassociated with the controller. The remotely located irrigation systemmay include a wireless communication unit connected to the controllerfor receiving data or sending data. The remotely located irrigationsystem may include manual data input associated with the controller.

The controller may be constructed to provide control signals to at leasttwo actuators, each associated with one valve device and located nearand connected to the water input port, wherein the valve device isconstructed to receive control signals from the controller for providingwater to a water delivery unit.

The controller may be constructed as a time based controller, or as anon-time based controller.

The irrigation system may be constructed to be removably located at aselected location. The irrigation system may be constructed to bemounted on a mobile irrigation platform. The mobile irrigation platformmay be self-propelled.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 1A are perspective views of a stationary water deliveryunit.

FIG. 1B is a detailed perspective view of the water delivery unit ofFIG. 1 also showing various controls located therein.

FIG. 1C is a perspective view of a mobile platform for the waterdelivery unit of FIG. 1.

FIG. 2 is a block diagram of a sensor and control system for a singlezone of the water delivery unit of FIG. 1.

FIGS. 3 and 3A show schematically two embodiments of a control systemfor the water delivery unit of FIG. 1.

FIG. 4 shows schematically a precipitation sensor that can be used inthe water delivery unit of FIG. 1.

FIGS. 5 and 5A show schematically two embodiments of a soil humiditysensor that can be used in the water delivery unit of FIG. 1.

FIG. 6 shows schematically a multizone, in ground irrigation systemincluding a multiplicity of local valves and sprinkler units.

FIG. 6A shows schematically a multizone in ground irrigation systemincluding a pressure communication system.

FIG. 6B shows schematically a single water delivery unit and anassociated valve assembly for the multizone water delivery unit of FIG.6 or 6A.

FIG. 7 is a block diagram of a sensor and control system for amulti-zone water delivery unit.

FIG. 8 is a perspective exploded view of a valve device used in thewater delivery unit of FIG. 1.

FIG. 8A is an enlarged cross-sectional view of the valve device shown inFIG. 8.

FIG. 8B is an enlarged cross-sectional view of the valve device shown inFIG. 8A, but partially disassembled for servicing.

FIG. 8C is a perspective view of the valve device of FIG. 1 including aleak detector.

FIG. 9 is an enlarged cross-sectional view of a moving piston-likemember used in the valve device shown in FIGS. 8, 8A, and 8B.

FIG. 9A is a detailed perspective view of the moving piston-like membershown in FIG. 9

FIG. 9B is an enlarged cross-sectional view of another embodiment of themoving piston-like member that can be used in the valve shown in FIGS.8, 8A, and 8B.

FIG. 10 is a cross-sectional view of a first embodiment of anelectromechanical actuator used in the valve shown in FIGS. 8, 8A and8B.

FIG. 10A is a perspective exploded view of the electromechanicalactuator shown in FIG. 10

FIG. 10B is a cross-sectional view of a second embodiment of anelectromechanical actuator used in the valve shown in FIGS. 8, 8A and8B.

FIG. 10C is a cross-sectional view of a third embodiment of anelectromechanical actuator for controlling the valve shown in FIGS. 8,8A and 8B.

FIG. 10D is a cross-sectional view of another embodiment of a membraneused in the actuator shown in FIGS. 10, 10A, 10B and 10C.

FIG. 10E is a cross-sectional view of another embodiment of the membraneand a piloting button used in the actuator shown in FIGS. 10, 10B and10C.

FIG. 11 is a block diagram of a control subsystem for controllingoperation of the electromechanical actuator shown in FIG. 10, 10B or10C.

FIG. 11A is a block diagram of another embodiment of a control subsystemfor controlling operation of the electromechanical actuator shown inFIG. 10, 10B or 10C.

FIG. 11B is a block diagram of data flow to a microcontroller used inthe control subsystem of FIG. 11 or 11A.

FIGS. 12 and 12A show the relationship of current and time for the valveactuator shown in FIG. 10, 10B or 10C connected to a water line at 0 psiand 120 psi in a reverse flow pressure arrangement, respectively.

FIG. 12B shows the dependence of the latch time on water pressure (in areverse flow pressure arrangement) for various actuators.

FIGS. 13 and 13A illustrate a pressure-based communication algorithm forthe communication system shown in FIG. 6A.

FIGS. 14A and 14B depict Table 1 and Table 2, respectively, whichillustrate communication time schedule and code for the communicationsystem shown in FIG. 6A.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The described irrigation systems use different types of communicationsystems for irrigation providing controlled amounts of water orproviding metered amounts of water delivered from one or severalirrigation zones. The irrigation systems are either above-ground orin-ground and use different control systems, valves and sensors, asdescribed below.

A single zone irrigation system 10 or 40 includes a remotely locatedcontroller connected to receive data from at least one local sensor, andincludes a valve device actuated by an actuator. The irrigation systemhas a water input port constructed to be coupled to a water conduitreceiving water from a remotely located water source. The controller islocated near the water input port and provides control signals to theactuator. The actuator initiates the on and off states of the valvedevice for providing water to a sprinkler or a drip irrigation device.

A multizone irrigation system 230A includes a central control unithaving a central controller interfaced with a central communicationunit. There may be a central valve that regulates water flow forirrigation from a water source. The central communication unit isconstructed to transmit or receive communication signals providingirrigation information, as shown in Tables 1 and 2. Each zone includesan irrigation control unit (e.g., a sprinkler control unit) constructedto control irrigation from a sprinkler, a drip irrigation device, orsimilar. The sprinkler control unit includes a local controllerinterfaced with a local valve for controlling water flow to thesprinkler. The sprinkler control unit also includes a localcommunication unit constructed to receive communication signals from thecentral communication unit and provide received irrigation informationto the local controller.

In a bi-directional communication system, one or several localcommunication units (associated with irrigation control units) areconstructed to transmit communication signals to the centralcommunication unit, which provides the received information to thecentral controller. The central controller thus can store specificirrigation cycles including the water amount delivered by each sprinkleror each zone. The local controller controls operation of the local valvebased on the irrigation information received from the central controllerand information provided by the individual local sensors.

FIGS. 1, 1A, and 1B show a stationary above-ground water delivery unit10, which includes several sensors and a controller for automateddelivery of selected amounts of water depending on the environmentalconditions. The water delivery (irrigation) unit 10 includes water inputport 22, a sprinkler 24, and an environmentally sealed body 26 supportedon a stake 28. The water delivery unit 10 is located remotely from awater source (or a faucet) and is connected to a water hose (or a waterpipe) at port 22. The module's body 26 includes a user interface controlunit 30 sealably enclosed by door 29 to be protected from moisture andother elements. The module's body includes one or several ports forvarious sensors, for example, sensors 64 through 72 described inconnection with FIGS. 2 through 5A. For example, module body 26 includesa port 34 with a transparent cover for a light sensor 70 (shown indiagrammatically FIGS. 2 and 7) and a port 36 providing thermallyconductive coupling for a temperature sensor 72 (also showndiagrammatically in FIGS. 2 and 7).

Sprinkler 24 is controlled by a control system and an actuator, alldescribed below in connection with FIGS. 10 through 11B. The controlsystem controls the spray pattern of the sprinkler. The sprinkler may belocated at a selected height and angle to achieve a desired coveragearea, depending on the water pressure and the flow orifices. Userinterface and controls 30 include various input display and indicatorelements described in connection with the embodiment of FIGS. 3 and 3A.Sprinkler 24 may have various embodiments described in U.S. Pat. No.4,580,724; 5,031,835; 5,031,833; 5,238,188; 5,695,122; or 6,164,562 allof which are incorporated by reference.

Water delivery unit 10 is an automated system controlled by amicroprocessor that executes various modes of operation. Preferably, theentire water delivery unit 10 is battery operated. Water delivery unit10 can provide a preprogrammed water delivery without measuring the“local conditions” or by measuring the “local conditions” using one orseveral sensors. The sensor date may be used to override a pre-selectedalgorithm (such as skip one watering course after detecting rain).Alternatively, water delivery unit 10 can provide water delivery basedon a local loop feedback control by measuring local conditions such asprecipitation, humidity, soil moisture, temperature and/or light andusing the measured data to deliver a selected amount of water at varyingwater pressures.

Water delivery unit 10 includes a water pressure sensor (e.g., a sensorsystem described in connection with FIGS. 11 through 12B), whichdetermines the local water pressure. The local controller includes amemory with stored properties of sprinkler 24 (or another water deliverydevice such as a drip irrigation system). Based on the orifice size ofsprinkler 24 and the control valve, a controller calculates the waterdelivery time for delivering a desired amount of water over theirrigated area. (This approach differs significantly from the timedwater delivery of many prior art systems, where the delivered amount ofwater varies due to varying water pressure. This approach also differsfrom many prior art systems, where the water pressure or orifice sizesare not known.)

The present systems and methods are also highly suitable for wateringlarge areas such as parks, golf courses, or agricultural fields usingwater delivery unit 10, where the “local” conditions vary due to anuneven terrain (e.g., small hills with dry soil or valleys where waterhas accumulated), and due to different soil, or different vegetation.The present systems and methods are also highly suitable for fields ororchards where different agricultural products are grown. In each case,the local controller receives data from at least one sensor andcalculates the desired water amount using stored algorithms. Based onthe local water pressure, water delivery unit 10 delivers the calculatedwater amount over the irrigated area. The design of water delivery unit10 is also highly suitable for using “gray water” pumped or deliveredfrom canals or water reservoirs. The present design of valves andactuators (described in connection with FIGS. 8 through 10E) doesn't geteasily plugged by sand or small particles.

FIG. 1C illustrates a mobile irrigation platform 40, which operatessimilarly to water delivery unit 10. Mobile irrigation platform 40includes a frame 42, one or several sprinklers 44 and 46, and a body 48.Sprinklers 44 or 46 may have various embodiments described in U.S. Pat.No. 4,580,724; 5,031,835; 5,031,833; 5,238,188; 5,695,122; or 6,164,562all of which are incorporated by reference.

Mobile irrigation platform 40 also includes two rear wheels 50 and 52,both of which are independently propelled by water pressure from a watersupply (not shown in FIG. 1C), and a front wheel 54. The movement ofeach rear wheel 50 and 52 is actuated by a solenoid valve (or anotherelectromagnetic actuator) located at the input of each wheel so as tocontrol its propulsion. Rear wheels 50 and 52 also include therespective brakes 56 and 58 actuated by water pressure. This arrangementprovides the stopping and starting of irrigation platform 40 and enablesits left-right rotation by means of shutting off the water supply to anyone of wheels 50 or 52, or brakes 56 or 58. The corresponding actuatorsare controlled by a microcontroller located inside body 48. Body 48 alsoincludes a local navigation device for directing or monitoring theplatform's motion.

To achieve a straight-line motion with both valves to both wheels 50 and52 open, irrigation platform 40 uses a proportional flow valvearrangement that provides a desired rate of the water supply to thepropelled wheels. The proportional flow valve arrangement is placed at alocation having equal distance to each wheel so as to insure equal rateof the wheel rotation. Furthermore, each wheel 50 or 52 is mounted ontoframe 42 using a spring-loaded independent suspension arrangement (notshown in FIG. 1C). The spring-loaded independent suspension arrangementprovides conformance to ground at different heights that may bedifferent for each wheel at times.

Front wheel 54 is spinning free (i.e., is not self-propelling as wheels50 and 52), but is equipped with two rotation encoders. The firstrotation encoder determines the forward or reverse motion. The secondrotation encoder is located inside an enclosure 55. The second rotationencoder determines the wheel's clockwise or counterclockwise rotationwith respect to frame 42. That is, the second encoder measures the leftor right side turns by monitoring the rotational axis of a fork 53,which secures wheel 54 to frame 42. Detailed description of the rotationencoders is provided in U.S. Provisional Application 60/337,112, filedon Dec. 4, 2001, entitled “Cart Management System,” published as US2003/0102969, on Jun. 5, 2003, which is incorporated by reference.

Sprinklers 44 and 46 have their spray nozzles directed at a selectedangle (for example, downward with a slight outward angle so as to obtaina spray coverage to the left, right, front and rear of the frame'soutline). Each sprinkler 44 or 46 is controlled by the control systemand the actuator described below. The control system controls the spraypattern and the water amount. The sprinklers may be located at aselected height or may even be telescopically elevated at actuation toprovide a longer trajectory and to enable watering of areas that theplatform cannot access. Each sprinkler 44 and 46 may include a solenoidcontrolled, proportional flow valve that enables turning on/off of eachindividual sprinkler (or sprayer) and enables control of the spraydistance and trajectory.

Mobile irrigation platform 40 includes a water inlet port (not shown)connectable to a garden hose. The water inlet port enables 360° rotationwith respect to the water supply hose with further means of insuringthat the platform will not override the hose by virtue of a rotatingright angle rigid arm, which will extend and retain the hose beyond theplatform traversing path.

FIG. 2 shows schematically the control system for a single zoneirrigation platform 10. Control system includes a controller 62 forcontrolling operation of a valve actuator 80 constructed and arranged tocontrol water delivery to at least one sprinkler (or another type of anirrigation device). Different types of valves, sensors, actuators andcontrollers are described below, all of which are preferably batteryoperated. Controller 62 may be connected to one, two or more sensors.For example, controller 62 is connected to a precipitation sensor 64, ahumidity sensor 66, a soil moisture sensor 68, a light sensor 70 and atemperature sensor 72. Controller 62 may also be connected to a leaksensor 78 for detecting and indicating a water leak present in the waterdelivery unit, e.g., at a remote location, or in the ground.

Control system 60 may be connected to other external controllers,sensors, or a central operation unit using standard wires.Alternatively, control system 60 may communicate with other externalunits using a device described in U.S. patent application Ser. No.09/596,251, filed on Jun. 16, 2000, and PCT Application PCT/US01/40913,entitled “Method and Apparatus for Combined Conduit/Electrical ConductorJunction Installation,” which is incorporated by reference.

Alternatively, control system 60 uses a wireless communication unit 76for sending data to or receiving data from a central communication unit,for downloading software or input data into the memory of controller 62,or for receiving remote sensor data. Controller 62 may also include oneor several displays and a manual data input 74. Depending on a controlalgorithm and the data received from one or several sensors 64 through72, controller 62 provides ON and OFF signals to valve actuator 80,which opens or closes water delivery. Preferably, valve actuator 80actuates a valve device 250 described in connection with FIGS. 8 through8B. Alternatively, valve actuator 80 may control various other types ofvalves, such as a diaphragm valve, a piston valve, ball valve, or anyother valve known in the field.

Referring to FIGS. 3 and 3A, stationary water delivery unit 10 or mobilewater delivery unit 40 include user interface controls 30A. Userinterface controls 30 (or 30A) include several switches, selectors andindicators including a rain sensor indicator 102, a photo sensorindicator 104, a temperature sensor indicator 106, and a humidity sensorindicator 108 (whereas the module's body includes the corresponding rainsensor, the photo sensor, the temperature sensor, and the humiditysensor). User interface controls 30 (or 30A) also include a soilselector 110, a vegetation-type selector 112, and a daytime (AM, PM)selector 116, all of which may also include associated indicators. Userinterface controls 30 or 30A also include a watering location indicator120 and a rain delay indicator 122, which is constructed and arranged toindicate no watering due to precipitation as detected by rain sensor 64.

The entire control and indicator system is packaged in a robust, outdoorsealed container capable of withstanding humid and hot or coldenvironment and also capable of withstanding mechanical shocks due torough handling. For example, the photo-sensor is located behind a clearwindow, and the temperature sensor is located inside a temperatureconductive conduit protecting the temperature sensor and providing goodthermal coupling. Rain sensor 64 includes opening 32 covered by aremovable screen and wire mesh, as described below in connection withFIG. 4. Watering time selector 116 includes two switches constructed andarranged to select daylight or night watering time and their frequency.For example, a user can select two nighttime waterings, the first oneseveral hours after sunset and the second one half hour before sunrise.Each switch includes a built in visible indicator constructed andarranged to indicate the selected watering schedule.

Still referring to FIGS. 3 and 3A, soil selector 110 includes, forexample, three switches constructed and arranged for a user to selectthe type of soil to be irrigated. Based on the type of soil, themicrocontroller automatically adjusts the watering schedule and volumeoptimal for the selected type of soil and vegetation based on thevegetation type selected by selector 112. Both soil selector 110 andvegetation-type selector 112 may include a visible indicator such as alight emitting diode (LED). User interface controls 30 or 30A alsoinclude a power switch 101 and may include an RF communication module(module 76 shown in FIG. 2 or 7) constructed and arranged to receivecommands related to various watering cycles.

The rain sensor detects the amount of natural precipitation and providesthe corresponding signal to the microcontroller. The microcontroller maydelay a watering cycle based on the amount of precipitation. The latewatering cycle is displayed to a user by rain delay indicator 122. Raindelay indicator 122 includes a single color visible LED, or anotherindicating element. A user can manually select the vegetation type usingvegetation type selector 112. The selected type of vegetation is thenindicated by one of four single color visible LEDs. (Alternatively, asingle multi-color or two dual color light indicators may be used.)

For example, in the embodiment where controls 30 are constructed andarranged as a hose-end controller (as shown in FIGS. 1, 1A and 1B), auser will physically move the hose-end controller, including the hoseconnected to a water source, to another location. Watering locationindicator 120 indicates the location so that this location and priorlocations will be communicated to another user (or the same user withoutneeding to remember the locations). The selected locations may bechanged, for example, once a day so that a parcel of land is wateredonce every three or four days depending on a selected algorithm.

FIG. 3A schematically illustrates another embodiment of the remotelocation control unit, that is, remote location control unit's userinterface 30A. User interface controls 30A include rain sensor 102,photo sensor 104, temperature sensor 106, humidity sensor 108, wateringlocation indicator 120, soil selector 110, and vegetation type selector112. User interface 30A's remote location controls also include a clock126, with an associated clock-adjust knob, and an associated AM-PMselector 116. The selected time may be stored in the memory ofcontroller 62.

FIG. 4 shows schematically a rain sensor (or precipitation sensor) 64.The rain sensor includes an input port 32 (seen on bodies 26 and 48), afunnel-shaped member 132, and a detector 140. The input port 32 includesa coarse convex inlet screen and a fine concave inlet screen 131 foreliminating solid contaminants and transmitting only water.Funnel-shaped member 132 includes a funnel inlet 134 and a funnel drainport 136 having a size that ensures that accumulated water will exit informs of droplets. Detector 140 includes piezo-electric sensor 144 andelectric-electric element 146. Piezo-electric disk 144 is positioned atan optimal location using positioning elements 142. Piezo-electricsensor 140 includes a sealed junction with electrical conduits exitingfrom the main body via one or several conduits. The droplet sensor 140detects the size and frequency of the individual droplets exiting funneldrain port 136. The size and frequency of the droplets depends on theamount of water accumulated inside funnel-shaped member 132.

FIG. 5 shows schematically a ground moisture sensor or a soil moisturesensor 150. Soil moisture sensor 150 (i.e., soil moisture sensor 68)includes a rigid containment chamber 152 with a semi-permeable membrane154 and two ports 156 and 158. Refill port 158 is used to deliver liquidinside rigid containment member 152, and pressure measurement port 156is used to measure pressure above liquid level in cavity 159 insiderigid containment chamber 152. Soil moisture sensor is inserted intosoil 149 so that semi-permeable membrane 154 is completely insertedinside the soil. Membrane 154 allows migration of water molecules fromcontainment chamber 152 to the soil, wherein the migration rate dependson the hygroscopic force (F) between the soil and the liquid insidecontainment chamber 152. The hygroscopic force, of course, depends onthe moisture content inside soil 149. Due to the water migration, thereis reduced pressure in region 156, which is detected by a pressuresensor located inside body 26 (and indicated by user interface controls30). The ground moisture sensor of FIG. 5 is relatively independent ofthe type of the soil because the hygroscopic force is predominantlyrelated to the moisture content of the soil and the type of the soilplays a very small part in the algorithm. Therefore, the ground moisturesensor does not need to be calibrated each time when inserted insidesoil 149.

FIG. 5A shows schematically another embodiment of the ground moisturesensor 150A (i.e., soil moisture sensor 68). Soil moisture sensor 150Aincludes a rigid containment chamber 152, a semi-permeable membrane 154and a liquid fill port 158. Inside rigid containment chamber 152 thereis a float 164 including two magnets 166 and 168 (generally, one orseveral magnets may be used). Float 164 is cooperatively arranged with areed sensor 162 located on the external surface of, or associated with,rigid containment chamber 152.

The ground moisture sensor is filled with liquid through liquid refillport 158. Float 164 is located near or at the liquid surface, dependingon its construction. Due to the hygroscopic force (F) directed frominside of rigid containment chamber 152 toward soil 149, water migratesfrom inside of chamber 154. As the liquid seeps out throughsemi-permeable membrane 154, water level drops, which changes thelocation (the relative height) of float 164. Reed sensor 162 detectslocation of magnets 166 or 168 and provides a signal to themicrocontroller regarding the water level inside rigid containmentchamber 152. Based on this electrical signal the ground moisture contentis determined using a calibration curve. Thus the microcontrollerreceives information about the ground moisture from the ground moisturesensor 150 or 150A. There may be several ground moisture sensors locatedaround the water territory and these may be hardwired to themicrocontroller or may provide information using RF or other wirelesscoupling.

Another embodiment of soil moisture sensor 64 includes two electrodeslocated on a stake and insertable in the ground. The two electrodes areseparated by a predetermined distance. The resistance or ion migrationbetween the two electrodes varies depending on the ground moisture. Theelectrodes may be made of metals providing a different potential andthus causing migration of ions there between. A measurement circuitconnected to the two electrodes measures the corresponding potential.Alternatively, the two electrodes may be made of an identical,non-corrosive metal (e.g., stainless steel 300 series) connected to anelectrical circuit. The electrical circuit provides a two-point or afour-point measurement of electrical conductivity between theelectrodes, which conductivity corresponds to the soil moisture. Themeasured conductivity data is provided to a microcontroller 62, whichthen determines the moisture content of the soil and determines theirrigation cycle according to a selected algorithm. Alternatively, atleast one of the electrodes may include conductive and isolating regionslocated at different depths in the ground. Based on the conductivityvalue measured at different levels, the moisture sensor measures themoisture profile at different depths in the ground. Again,microcontroller 62 uses the depth moisture profile for calculating anappropriate irrigation cycle.

Alternatively, the ground moisture sensor may be a capacitive sensorhaving a porous dielectric. The dielectric material is in contact withthe ground and water migrates between the capacitive plates by thecapillary effect from the ground. Depending on the ground moisture, thedielectric constant of the capacitor varies. Thus, the capacitance valuecorresponds to measured moisture content of the ground.

According to another embodiment, the ground moisture sensor (i.e., thesoil moisture sensor) includes a gypsum board coated with a waterpearmeable film and two electrodes located inside the gypsum board andseparated by a predetermined distance. The moisture sensor measures theresistance between the two electrodes, which corresponds to the groundmoisture migrating into the gypsum material.

FIG. 6 shows schematically a multizone in-ground water delivery unit230. Water delivery unit 230 includes a control module with controlsystem 60A and a plurality of water pipes 232 and 234 for deliveringwater to a number of valves 250 and a number of in-ground sprinklers, asshown in FIG. 6B. Control system 60A is shown in detail in FIG. 7.

Referring to FIG. 6B, a sprinkler system 236 includes a sealed enclosure238 for housing a valve 250 and optionally local control system 60 (orlocal control system 235). Coupled to enclosure 238 is a housing 240 anda protective cover 241, all of which are located in ground 149. Housing240 includes a pop-up element 242 having a water delivery port (or asprinkler) located generally at a distal end 244. Pop-up element 242also includes a vertical antenna 246 coupled to wireless communicationunit 76 (FIG. 2) for wireless communication. According to anotherembodiment, the pop up vertical antenna is constructed independentlyfrom the sprinkler and includes a metal element raised and lowered bywater pressure delivered from valve 250, or a spring-loaded metalelements raised by water pressure and retracted by a spring.

The present design may be used with various embodiments of in groundpop-up (riser) sprinklers described in U.S. Pat. Nos. 4,781,327;4,913,351; 5,611,488; 6,050,502; 5,711,486; and US Patent Publications2001/0032890; 200210092924; 2002/0153432, all of which are incorporatedby reference

Each valve 250 and the associated sprinkler 236 may include one controlsystem 60 (which in this embodiment is a local control system) locatedinside enclosure 238 and communicating with a central control orinterface system via antenna 246. Local control system 60 (shown in FIG.2) may also be connected to leak detector 78 for detecting water leaksat valve 250. Wireless communication unit 76 may include a transmitterand a receiver, or just a receiver. At a preselected time, pop-upelement 242 rises above ground 149 (by water pressure delivered fromvalve 250) and antenna 246 is used to establish wireless communication.Advantageously, most of the time, antenna 246 is retracted below groundthus eliminating any obstructions to people or machinery.

In general, a multizone irrigation system (e.g., irrigation system 230Ashown in FIG. 6A) includes a communication system for selectivelycontrolling different zones and delivering a selectable water amount (ordelivering different amounts of water according to the local irrigationneeds). The multizone irrigation system includes a central control unit300. Each zone includes a sprinkler control unit connected to asprinkler. Sprinkler control unit includes a local communication unitconstructed to receive communication signals from the centralcommunication unit and provide received irrigation information to thelocal controller. In a bi-directional system, one or several localcommunication units are constructed to transmit communication signals tothe central communication unit, which provides received information tothe central controller. The central controller thus can store specificirrigation cycles including the water amount delivered by each sprinkleror each zone. The local controller controls operation of the local valvebased on the irrigation information received from the central controllerand information provided by the individual local sensors.

According to another embodiment, the communication system is a wirelesscommunication system, wherein the central communication unit includes anRF transmitter and the local communication units include an RF receiver.Alternatively, both the central communication unit and the localcommunication units each include an RF transceiver. The wirelesscommunication system uses the rising antenna described above.

According to another embodiment, the communication system is ahard-wired communication system, wherein the communication wire islocated along the water pipes. This embodiment is described U.S. patentapplication Ser. No. 09/596,251, now U.S. Pat. No. 6,748,968, and PCTApplication PCT/US01/40913, entitled “Method and Apparatus for CombinedConduit/Electrical Conductor Junction Installation,” both of which areincorporated by reference.

According to yet another embodiment, the communication system uses watermedium in the irrigation pipes for transmitting communication messages.The messages between the central communication unit and the localcommunication units are transmitted using pressure waves. Thecommunication system utilizes ultrasound waves generated by apiezoelectric elements commonly used in ultrasound systems. The centralcommunication unit and each local communication unit include ultrasoundtransducers (or transducer arrays) for emitting and detecting ultrasoundwaves. The ultrasound transducer design, spacing and location arearranged to optimal transmission in water pipes depending on the pipelayout.

According to yet another embodiments, the communication system utilizesan acoustic/vibratory driver (electro magnetic or magnostrictive) at thecentral control unit. The acoustic/vibratory driver is coupled to thewaterline and each local control system includes an acoustic/vibratoryreceiver. The acoustic/vibratory driver generates waves in the watercolumn within the irrigation pipes and/or the piping walls. The wavescarry coded information transmitted from the central controller to thelocal controller. For bi-directional communication, each local controlsystem includes a driver next to the zone valve.

According to yet another embodiments, the communication system utilizesoscillating pressure waves propagating in the water conduits, whichwaves vary in rate, pulse width, and possibly in pulse magnitude. Thepressure oscillations are attained by an oscillating pump, a two-waysolenoid or another means residing at central controller unit 300. Thepressure waves are detected by pressure sensors 239 (or pressureswitches) associated with the sprinkler control units.

According to yet another embodiments, the communication system utilizespressure waves generated by opening and closing a valve and propagatingin the water conduits. This communication system is described in detailin connection with FIGS. 6A, 13A, 13B, 14A and 14B.

FIG. 6A illustrates an in-ground irrigation system 230A including auni-directional or bi-directional communication system utilizingpressure pulses. Irrigation system 230A includes a central control unit300 and sprinkler control units 231 ₁, 231 ₂, . . . 236 _(N). Centralcontrol unit 300 includes a central control system 60, a central valve302 (e.g., a solenoid valve, a rotary valve or another motorized valve)and a central pressure transducer (sensor) 304 for measuring waterpressure in the main input water line 301. One embodiment of the centralcontrol system 60 is described in connection with FIG. 2 and includes acentral controller (processor) 62. Sprinkler control unit 231 ₁ includesa local control system 235 ₁, a sprinkler 236 ₁, a local irrigationvalve 250 _(i) (e.g., a solenoid valve, a rotary valve or anothermotorized valve), and a local pressure transducer (sensor) 239 ₁. Allelements are powered by a battery. Similarly, sprinkler control unit 231₂ includes a local control system 235 ₂, a sprinkler 236 ₂, a localirrigation valve 250 ₂, and a local pressure transducer (sensor) 239 ₂.Again, all these elements may be powered by a battery.

All N sprinkler control units 231 _(N) include similar element elementsthough variation in the units is possible depending on the irrigationneeds. The sprinkler control units have a modular design enabling fieldmodification of the unit. That is, a technician installing or servicingthe units can add or remove various sensors. For example, some localcontrol systems 235 may include no soil or no humidity sensors, or othermay include no sensors at all, but all include a central controller(i.e., a processor, memory and communication interface). According toone preferred embodiment, each sprinkler control unit 231 includes aself-contained power supply unit for recharging the batteries. The powersupply unit includes a solar element utilizing the photovoltaic effectto provide power to the batteries. Alternatively, the power supply unitincludes a miniature water turbine utilizing the water flow energy forgenerating and providing electrical power to the batteries.

Central control system 60 communicates with the sprinkler units 231₁-231 _(N), utilizing changes in the water pressure as the signalingmeans. Central valve 302 is constructed to allow water to exit waterpipe 232 via a port 301 and thus lower water pressure in pipes 234.Sprinkler units 231 include local controllers 235 that control valves250 for sprinkling or for sending pressure signals by opening andclosing and thus lowering and restoring water pressure in pipes 234.Pressure sensors 239 detect the changes in water pressure thatconstitute the communication signals and provide the correspondingelectrical signal to local control systems 235.

Generally, each pressure sensor (transducer) 239 is made fromhigh-strength, watertight, non-corrosive material such as stainlesssteel. The input pressure range is, for example, between 0-414 kPa (or0-60 psi). The electrical output signal, between 4-20 mA, is then sentto the controller, which interprets the signal and uses it to determinethe next action in the irrigation system, including determining amountof watering, and sending back signals by changing the water pressure.The pressure gauge should have good repeatability, and be able toreproduce an identical signal each time the same pressure is applied toit under the same conditions. It should also have a short response time,or length of time required for an output signal to be produced when thepressure is sensed.

The programmable controller of each sprinkler unit 231 has interfacesfor receiving signals from pressure sensor 239, and for opening andclosing sprinkler valves 250 for pressure signaling (i.e., datacommunication) and sprinkling. Each local controller can be programmedto both receive input from the pressure gauge (corresponding tocommunication signals from central control unit 300) and to send signalsto central control unit 300, at particular time slots. The schedule forsignals receiving and transmitting of communication at particular timesis selected and designated for each sprinkler unit 231 to avoidcrosstalk or communication errors.

The communication system uses a stipulated code of pressure changes,sending and decoding messages conveyed by each coded signal. Centralcontrol system 60 transmits messages to the sprinkler units utilizingpressure changes to convey amounts of irrigation based on the variablesmeasured by the central system's sensors and/or preset values entered bya user using the system's controls. For example, central control systemprovides a set length of watering time one morning as based on rain thenight before, and given the vegetation the sprinklers were set to water,etc. Each sprinkler unit also detects variables such as the wetness ofthe soil at the sprinkler's location. Based on these measurements, eachsprinkler varies the amount of watering further refining the sensitivityof the system. If one sprinkler unit senses a higher amount of soilmoisture than the general system, it could water 20% more than theinstruction from the control system. If a sprinkler measuresprecipitation due to someone having watered the specific location with ahose, without having watered the entire property irrigated by the inground watering system, the sprinkler unit's controller can also thenreduce the amount it waters by a specific percentage. The magnitude ofthese changes is preset for each measurement involved.

Referring still to FIG. 6A, the communication signals are based on dropsin water pressure. The water pressure drops are initiated by controller235 _(n) opening valve 250 _(n) and letting water out of the water pipe.The water pressure goes up to its original value once the valve isclosed again allowing pressure to rise to the average water pipepressure once more. The rise in water pressure up to the main water pipepressure occurs relatively quickly once the valve is closed again. Thesedrops in pressure and rises to average pressure are used as codeelements (i.e., each “low pressure” and “standard pressure,” or L and Sshown in Table 1 and 2), where a certain combination of rises and dropsis detected by the pressure detectors, and is interpreted for irrigationpurposes. The combination “LSLS,” is executed by controller 235 openingthe valve, closing it, opening it once more, and closing it again, eachtime for one second or another time interval sufficient for pressurerecovery and detection.

Referring to Tables 1 and 2, each communication starts with a header(“LSLS”), so that any random change in water pressure is not read as amessage by the pressure sensor. Each message transmission also ends witha footer, so that the system could ascertain end of transmission. Inthis example, a 5 sec. lowering of pressure (i.e., “LLLLL”), where thevalve is open, allowing for water to exit the system, functions as afooter. (However, the unit interval may be shorter than 1 sec. Anddepends on the pressure recovery from “low” pressure to “standard”pressure.) Pressure detector 239 _(n) detects changes in the waterpressure and controller 235 _(n) “translates” the messages, anddetermines what messages to transmit. Controller 235 _(n) directsopening and closing of valve 250, therefore lowering or raising thewater pressure and sending the communication signal. The communicationmessage may include the following header, first coded term, spacer,second coded term, and footer (i.e., end of transmission string):LSLS/LSL/SSSSS/LSSL/LLLLL.

The code for each part of the message is selected depending on theamount of information being communicated, and how it is beingcommunicated. For example, if only one type of information is beingtransmitted, the code can be simpler, and the spacer may not benecessary. If more information is being communicated, the code can bemore complex, having more changes in pressure for each term. The sameterms can also have more than one meaning depending on their location inthe entire message. The controller and control unit can be made todistinguish each meaning as dependent upon the location of the termwithin the message.

Each sprinkler unit 231 may transmit a signal back to central controlunit 300 at a predetermined time to prevent cross-talk, as shown inTables 1 and 2. Local control system 235 _(i) can transmit a signalincluding the header, the code for the amount the watering varied fromthe amount required by control system 60 (“0-20% less”), the spacerbetween the two signals, and the code giving the reason for the lengthof the watering period (“humidity level”). Then control system 60transmits a message of its own to the sprinkler at the predeterminedtime. The reply message may include the header, and the code meaning“message received.” Controller 235 ₁ receives the signal via readingsfrom pressure detector 239 _(n), and does not attempt to send the signalonce more.

This pattern continues for each sprinkler unit. In the example shown,other sprinklers in the system have watered different amounts, and fordifferent reasons. For example, sprinkler 236 ₃ has watered 40-60% lessthan required due to the type light levels measured in its area.Sprinkler 236 ₄ has not varied the amount of watering required bycontrol unit 60 because of precipitation levels at its location. In thislast case, the control system did not receive the message, so thatsprinkler 236 ₄'s controller 235 ₄ have to resend its message to thecontrol system. It do so right away, within the two minutes allotted tothe control unit to communicate with sprinkler 236 ₄ to communicate, tomake sure the message was received before the next sprinkler unit sentits message, and so that the control unit not confuse two sprinklerunits' messages. This system has been used as an example only, and is byno means exclusive of embodiments, which can include new codes,meanings, times for communication, or message structures.

FIGS. 13A and 13B illustrate a communication algorithm for controllingirrigation system 230A (shown in FIG. 6A). Referring to FIG. 13A,initially each local control system performs a calibration of thestandard pressure in water pipe 232 (step 902). During the calibration,each pressure sensor 239 _(n) measures water pressure before any valveis opened, and provides the pressure to the associated local controller235 _(n). If no valves are open in the system, all the pressure readings(S₀₀ . . . . S_(0n)) in the system are substantially the same. If anymeasured pressure value for is lower than a pre-selected minimum at step904, the system has a water leak, or a similar problem. P_(min) is aspecified percentage (40 or 50% or another value specific to theirrigation system) of a normal pressure in the irrigation system in kPaor psi. Upon detecting a low water pressure, central control system 60records an error message (step 940) and stops the irrigation process(step 942). Minor leaks at some points in the system do not stop thewatering process, but are registered; error signals are transmitted tocentral control system 60. Each sprinkler control unit 231 detecting alower than normal pressure can separately shut down and not partake inthe irrigation process. As explained below, if a sprinkler unit does notsignal back to central control system 60, system 60 stores thatinformation and indicates that the error exists, to point it out andhave it serviced.

The value of having the standard pressure (S₀) calculated every time thesystem commences communication is twofold: any variances in waterpressure are offset, and leaks can be detected. Once standard pressureis calculated, central control system 60 communicates to local controlsystems 235 _(n) the amount of watering necessary for each sprinkler inthe system (step 906), based on central control system 60's sensors andcontrols.

At the allocated time, central control system 60 sends pressure-basedmessages to each local control 235 _(n) regarding the amount of wateringnecessary for the territory being irrigated (step 906). Once the messageis received, the sprinkler unit confirms the receipt of the message inthe time allotted for central control system-sprinkler unitcommunication (step 907).

Central control system 60 causes the sprinkler units to adjust theirirrigation amounts by its messages according to the desires of the user,and the central control system's sensors (step 910). Each local controlsystem 235 _(n) executes irrigation based on two types of input: (A) theirrigation data received from central control system 60, and (B)readings from their local sensors 64, 66, 68, 70, and 72. Specifically,the input from local sensors 64, 66, 68, 70, and 72 is used to adjustthe irrigation data received from central control system 60 at step 906.

As described in FIG. 14A, based on a soil humidity reading from soilsensor 68, local control system. 235 _(n) from sprinkler unit 3 reducesthe watering by 20% less than the value transmitted from central controlsystem 60. This is done, for example, for sprinkler systems located in alocal valley that received more surface water. Alternatively, theirrigation amount is increased based on a soil humidity reading fromsoil sensor 68 by a local control system located on a hill where thesoil has water loss.

If central control system 60 does not receive the sprinkler unitconfirmation (step 908), and the control system 60 has not sent themessage twice (step 944), it resends the message to the sprinkler unitin question (step 906). If central control system 60 transmits theirrigation message twice without return confirmation (step 944), itenters an error message for that sprinkler unit (step 948). If a messagehas not been sent to all sprinkler units, central control system 60(step 912) initiates transmission of the irrigation message to the nextsprinkler at the preselected time slot (step 908).

Table 1 (FIG. 14A) describes in further detail central control system 60(CU) irrigation messages to the sprinkler units (SUs), following theflow diagram in FIG. 13A. The top half of the table describes themessages from central control system 60 to the sprinkler units (steps902-906). The bottom half of the table describes the sprinkler units'confirmation messages to the central control system (steps 907, 948,944).

The time allocation for communicating with the local control systems ispre-selected depending on the number of sprinkler units and complexityof the irrigation instructions. For example, central control system 60transmits the irrigation instructions to local control system 235 ₁ tenminute after 6 AM for a pre-selected period of ten minutes. This is areserved time slot for local control system 235 ₁, which system “wakesup” and “listens” for irrigation instructions, while the other localcontrol systems 235 ₂ through 235 _(n) are inactive. Time slots of otherlengths can be selected.

As an example, if the preset timing for the start of the communicationalgorithm is 2:00 AM, pressure will be calibrated at 2:00-2:01 AM.Central control unit 60 has a time allotted for communication with eachsprinkler unit: in this case, the central control system 60 has allotted7 minutes for transmitting the irrigation message to sprinkler unit 1,and is ready at 2:10 AM to send the message. Similarly, sprinkler unit1's controller “listens” for the message at 2:10 AM. Central controlunit 60's irrigation message to sprinkler unit 1 consists of a header(“LSLS”), instructions for the irrigation time (“LLS”), and a footer(“LLLLL”), indicating the end of the message. The meaning of the messageis to water for one hour. Each message to the sprinkler units follows asimilar format.

Sprinkler unit 1 transmits its confirmation message at 2:18, sprinklerunit 2 at 2:28, etc. Similarly, the central control unit is ready toreceive these messages at these same times. The message follows the sameformat as above: a header (“LSLL”), a message received/not receivedsignal (“LSLL” or “LLS”), and a footer (“LLLLL”).

Referring again to FIG. 13A, central control system 60 checks if itreceived at least one confirmation (step 913). If not, it enters anerror message (step 915) and stops the irrigation process. This confirmsonce more that the sprinkler units are sending the messages, and thatthe central control unit is properly detecting them.

Referring now to FIG. 13B, once irrigation (step 914) occurs, eachsprinkler sends central control system 60 a message regarding how muchit watered, and why. The standard pressure is remeasured (S₁₀-S_(1n))for the central control unit and all sprinkler units. Again, if thismeasurement is not less than the set minimum (step 918), an errormessage is set (step 934) and the system stops (step 936).

If the pressure is set for signaling, the sprinkler units send centralcontrol system 60 the confirmation messages (step 920). The centralcontrol system sends back a confirmation to the sprinkler units at step921. If the sprinkler units do not receive confirmation (step 922), andthe sprinkler units have not sent the message twice already (step 928),the message is resent (step 920). However, if the message had alreadybeen sent (step 930), the central control unit sets an error message forfuture servicing (step 930).

These steps are further described in FIG. 14B, in which sprinkler unit 1is about to transmit its irrigation report to the central controlsystem. The top half of table 2 in FIG. 14B corresponds to the messagesfrom the sprinkler units' messages to the central control system (steps920, 928). The bottom half of the table describes the central controlsystem's confirmation message to the sprinkler units (steps 921, 922).Transmittal for sprinkler unit 1 is set for 6:10-6:18 AM, so thatcentral control system 60 is ready to receive at that time as well. Thesprinkler units and the central control unit has transmit and receivetimes set up so that each is transmitting and receiving simultaneously,and can associate the messages with each other. Sprinkler unit 1 sends amessage consisting of a header (“LSLS”), the signal for the amount itwatered (“LLS”), a spacer (“SSSSS”), a signal for the reason (“LSLL”),and a footer (“LLLLL”). In this case the message means that thesprinkler unit watered 0-20% less than was required by the centralcontrol system due to local humidity levels. Sprinkler units 1-4 sentdifferent messages, in the same format, giving different reasons for theway they irrigated. (See Table 2, FIG. 14B)

Central control system 60 then confirms the messages by each sprinklerunit. Again, there is a preset time that central control system 60transmits, and that the sprinkler units receive: for sprinkler unit 1,that is 6:18-6:22 AM. For sprinkler unit 2, 6:28-6:32 AM, etc. Themessages consist of a header, a received or not received message, and afooter (i.e., end of communication string).

At this point, if the central control system sent messages to all thesprinkler units (step 924), it shuts the system down until the nextscheduled communication. The system will then turn on, recalibrate, andcommunicate in the same manner as that described above.

The parameters described can be changed, and are not inclusive: the timefor communication, the number of times the message can be resent, thenumber of components (both for the sprinkler units and the centralcontrol system), and the nature of the messages, for example, can all bemodified.

According to another embodiment, an ultrasonic communication systemprovides communication between the central control unit and thesprinkler units. While water is an ideal medium for transmittingmechanical sound waves, the irrigation pipes may “complicate” thepropagation and detection of the signal. The system is similar to thesystem shown in FIG. 6A, but pressure detectors 239 are replaced bypiezoelectric transducers, and the control units include a pulserproviding electrical signals to the transducer. As known in the art, thetransducers' piezoelectric elements convert the controllers' electricalsignals into mechanical vibrations in the “transmit” mode. In the“receive” mode, the piezoelectric elements convert mechanical vibrationsinto electrical signals provided to the controllers.

In the ultrasonic communication system, the generated longitudinal soundwaves travel through the water in the water pipes. However, thecommunication system is sensitive to changes in the generated waves.Therefore, the ultrasonic communication system is designed with smoothpipes generally free of blemishes and discontinuities, which causeenergy reflections. The reflection sensitivity can, however, be used toprovide orientation and distance which can be used to identify thetransmitter. That is, once the control unit received a signal, thenature of the signal could be used to ascertain which sprinkler unit hadsent it. This is a desirable quality when setting up communicationcodes, particularly in simpler irrigation systems. In the ultrasoundcommunication system, the central control system communicates with thelocal control system using algorithms similar to flow diagram 900.However, since the ultrasound system enables a higher data transmissionrate, the communication code may be much more elaborate that the codeexamples provided in Tables 1 and 2.

Depending on the size and materials of the irrigation system, thescattering of the signals and their absorption could become a concern,and it may be necessary to have some of the sprinkler units relaysignals so they can more easily and clearly reach more remote parts ofthe system. Controllers at certain points along the system is programmedto resend signals to the control unit from sprinkler units further away,and vice-versa. The necessity for this relay could be reduced not onlyby optimizing the shape and size of the system, but also by generallyusing relay transmitters and strategic locations of ultrasonictransducers or selection of suitable arrays.

The above described communications systems increase their reliability byoptionally using an error control algorithm. The system can use either aforward error correction strategy (FEC) or an automatic repeat requeststrategy (ARR). The FEC algorithm, such as the Hamming code) providesfor error correction where a transmission error is detected. The ARQalgorithm initiates automatically retransmission if a communicationerror or corrupted data are detected. The FEC protocol is generally notpreferred for the irrigation communication system of FIG. 6A, sincere-transmission of the signal is possible. The FEC protocol requiresmuch more redundant information transmission than the ARQ protocol. Theredundancy requires a larger data transfer due largely to the fact thatthe number of overhead bits needed to implement an error detectionscheme is much less than the number of bits needed to correct the sameerror.

FIG. 7 illustrates diagrammatically a multi-zone irrigation controlsystem 60A. Irrigation control system 60A includes controller 62receiving data from one or several sensors 64 through 72, describedabove. Controller 62 provides drive ON or OFF signals to valve actuators80 ₁, 80 ₂, 80 ₃ . . . 80 _(N). Valve actuators 80 ₁, 80 ₂, 80 ₃ . . .80 _(N) actuate individual valve devices that in turn provide water toseparate sprinklers (or any other irrigation units). Again, controller62 may have an associated wireless communication unit 76 for sendingdata to, or receiving data from, a central communication unit, a remotesensor, or any other device.

FIGS. 8, 8A and 8B illustrate an automatic valve device 250 constructedand arranged for controlling water flow in water delivery unit 10, 40,or 236. Specifically, automatic valve device 250 receives water at avalve input port 252 and provides water from a valve output port 254, inthe open state. Automatic valve device 250 includes a body 256 made of adurable plastic or metal. Preferably, valve body 256 is made of aplastic material but includes a metallic input coupler 260 and ametallic output coupler 280. Input and output couplers 260 and 280 aremade of metal (such as brass, copper or steel) so that they can providegripping surfaces for a wrench used to connect them to a water lineinside water delivery unit 10 (or in ground unit 236). Valve body 256includes a valve input port 290, and a valve output port 294.

Metallic input coupler 260 is rotatably attached to input port 290 usinga C-clamp 262 that slides into a slit 264 inside input coupler 260 andalso a slit 292 inside the body of input port 290. Metallic outputcoupler 280 is rotatably attached to output port 294 using a C-clamp 282that slides into a slit 284 inside output coupler 280 and also a slit296 inside the body of output port 294. When servicing delivery unit 10(or in ground unit 236), this rotatable arrangement prevents tighteningthe water line connection to any of the two valve couplers unlessattaching the wrench to the surface of couplers 260 and 280. (That is, aservice person cannot tighten the water input and output lines bygripping on the valve body 256.) This protects the relatively softerplastic body 256 of automatic valve device 250. However, body 256 can bemade of a metal in which case the above-described rotatable coupling isnot needed. A sealing O-ring 266 seals input coupler 260 to input port290, and a sealing O-ring 288 seals output coupler 280 to input port294.

Referring to FIGS. 8, 8A, and 8B, metallic input coupler 260 includes aninflow adjuster 270 cooperatively arranged with a flow control mechanism360. Inflow adjuster 270 includes an adjuster piston 272, a closingspring 274 arranged around an adjuster pin 276 and pressing against apin retainer 268. Inflow adjuster 270 also includes an adjuster rod 278coupled to and displacing adjuster piston 272. Flow control mechanism360 includes a spin cap 362 coupled by screw 364 to an adjustment cap366 in communication with a flow control cam 370. Flow control cam 370slides linearly inside body 256 upon turning adjustment cap 366. Flowcontrol cam 370 includes inlet flow openings 371, a locking mechanism373 and a chamfered surface 374. Chamfered surface 374 is cooperativelyarranged with a distal end 279 of adjuster rod 278. The linear movementof flow control cam 370, within valve body 256, displaces chamferedsurface 374 and thus displaces adjuster rod 278. Adjuster piston 272also includes an inner surface 273 cooperatively arranged with an inletseat 261 of input coupler 260. The linear movement of adjuster rod 278displaces adjuster piston 272 between a closed position and an openposition. In the closed position, sealing surface 273 seals inner seat261 by the force of closing spring 274. In the opened position, adjusterrod 278 displaces adjuster piston 272 against closing spring 274 therebyproviding a selectively sized opening between inlet seat 261 and sealingsurface 273. Thus, by turning adjustment cap 366, adjuster rod 278 opensand closes inflow adjuster 270. Inflow adjuster 270 controls the waterinput flow to sprinkler 24. The above-described manual adjustment can bereplaced by an automatic motorized adjustment mechanism controlled bymicrocontroller 62.

Referring still to FIGS. 8, 8A and 8B, automatic valve device 250 alsoincludes a removable inlet filter 380 removably located over an inletfilter holder 382, which is part of the lower valve housing. Inletfilter holder 382 also includes an O-ring and a set of outlet holes 317shown in FIG. 9. The “fram” piston 326 is shown in detail in FIG. 9A.Water flows from input port 252 of input coupler 260 through inflowadjuster 270 and then through inlet flow openings 371, and through inletfilter 380 inside inlet filter holder 382. Water then arrives at aninput chamber 318 inside a cylindrical input element 324 (FIG. 9)providing pressure against a pliable member 328.

Automatic valve device 250 also includes a service loop 390 (or aservice rod) designed to pull the entire valve assembly, includingattached actuator 80, out of body 256, after removing of plug 366. Theremoval of the entire valve assembly also removes the attached actuator80 and piloting button 705 (shown in FIG. 10). To enable easyinstallation and servicing, there are rotational electrical contactslocated on a PCB at the distal end of actuator 80. Specifically,actuator 80 includes, on its distal end, two annular contact regionsthat provide a contact surface for the corresponding pins, all of whichcan be gold plated for achieving high quality contacts. Alternatively, astationary PCB can include the two annular contact regions and theactuator may be connected to movable contact pins. Such distal, actuatorcontact assembly achieves easy rotational contacts by just slidingactuator 80 located inside valve body 502.

FIG. 8C illustrates automatic valve device 250 including leak detector78 (FIG. 2) for indicating a water leak or water flow across valvedevice 250. Leak sensor 78 includes electronic measurement circuit 500and at least two electrodes 502 and 504 coupled respectively to inputcoupler 260 and output coupler 280. (The leak sensor may also includefour electrodes for a four-point resistivity measurement). Valve body256 is made of plastic or another non-conductive material. In the closedstate, when there is no water flow between input coupler 260 and outputcoupler 280, electronic circuit 500 measures a very high resistancevalue between the two electrodes. In the open state, the resistancevalue between input coupler 260 and output coupler 280 dropsdramatically because the flowing water provides a conductive path.

There are various embodiments of electronics 500, which can provide a DCmeasurement, an AC measurement including eliminating noise using alock-in amplifier (as known in the art). Alternatively, electronics 500may include a bridge or another measurement circuit for a precisemeasurement of the resistivity. Electronic circuit 500 provides theresistivity value to microcontroller 62 and thus indicates when valvedevice 250 is in the open state. Furthermore, leak sensor 78 indicateswhen there is an undesired water leak between input coupler 260 andoutput coupler 280. The entire valve 250 is located in an isolatingenclosure (e.g., enclosure 26 in FIG. 1, or enclosure 238 in FIG. 6A) toprevent any undesired ground paths that would affect the conductivitymeasurement. Furthermore, leak sensor 78 can indicate some other valvefailures when water leaks into enclosure 26 or 238 from valve device250. Thus, leak detector 78 can sense undesired water leaks that wouldbe otherwise difficult to observe. Leak detector 78 is constructed todetect the open state of the irrigation system to confirm properoperation at a remote location.

Automatic valve device 250 may include a standard diaphragm valve, astandard piston valve, or a novel “fram” piston valve 320 explained indetail in connection with FIGS. 9, 9A, and 9B. Referring to FIG. 9,valve 320 includes distal body 324, which includes an annular lip seal325 arranged, together with pliable member 328 (FIG. 9A), to provide aseal between input port chamber 318 and output chamber 319. Distal body324 also includes one or several flow channels 317 (also shown in FIG.8) providing communication (in the open state) between input chamber 318and output chamber 319. Pliable member 328 also includes sealing members329A and 329B arranged to provide a sliding seal, with respect to valvebody 322, between pilot chamber 342 and output chamber 319. There arevarious possible embodiments of seals 329 a and 329 b (FIG. 9). Thisseal may be a one-sided as seal or two-sided seal 329A and 329B shown inFIG. 9. Furthermore, there are various additional embodiments of thesliding seal including O-rings, etc.

The present invention envisions valve device 326 having various sizes.For example, the “full” size embodiment has the pin diameter A=0.070″,the spring diameter B=0.360″, the pliable member diameter C=0.730″, theoverall fram and seal's diameter D=0.812″, the pin length E=0.450°, thebody height F=0.380″, the pilot chamber height G=0.280″, the fram membersize H=0.160″, and the fram excursion I=0.100″. The overall height ofthe valve is about 1.39″ and diameter is about 1.178″.

The “half size” embodiment of the “fram piston” valve has the followingdimensions provided with the same reference letters. In the “half size”valve A=0.070″, B=0.30, C=0.560″, D=0.650″, E=0.38″, F=0.310″, G=0.215″,H=0.125″, and I=0.60″. The overall length of the ½ embodiment is about1.350″ and the diameter is about 0.855″. Different embodiments of the“fram piston” valve device may have various larger or smaller sizes.

Referring to FIGS. 9 and 9A, the fram piston valve 320 receives fluid atinput port 318, which exerts pressure onto diaphragm-like member 328providing a seal together with a lip member 325 in a closed state.Groove passage 338 provides pressure communication with pilot chamber342, which is communicates with actuator cavity 350 via passages 344Aand 344B. An actuator (shown in FIG. 10, 10A or 10B) provides a seal atsurface 348 thereby sealing passages 344A and 344B and thus pilotchamber 342. When the plunger of actuator 80 or 81 moves away fromsurface 348, fluid flows via passages 344A and 344B to control passage346 and to output chamber 319. This causes pressure reduction in pilotchamber 342. Therefore, diaphragm-like member 328 and piston-like member332 move linearly within cavity 342, thereby providing a relativelylarge fluid opening at lip seal 325. A large volume of fluid can flowfrom input port 318 to output chamber 319.

When the plunger of actuator 80 seals control passages 344A and 344B,pressure builds up in pilot chamber 342 due to the fluid flow from inputport 318 through “bleed” groove 338. The increased pressure in pilotchamber 342 together with the force of spring 340 displace linearly, ina sliding motion over guide pin 336, fram piston 326 toward sealing lip325. When there is sufficient pressure in pilot chamber 342,diaphragm-like pliable member 328 seals input port chamber 318 at lipseal 325. The soft member 328 includes an inner opening that is designedwith guiding pin 336 to clean groove 338 during the sliding motion. Thatis, groove 338 of guiding pin 336 is periodically cleaned. Therefore,fram piston 326 is uniquely designed for controlling flow of “unclean”water (“gray water”) for irrigation.

The embodiment of FIG. 9 shows the valve having a central input chamber318 (and guide pin 336) symmetrically arranged with respect to ventpassages 344A and 344B (and the location of the plunger of actuator 80).However, the valve device may have input chamber 318 (and guide pin 336)non-symmetrically arranged with respect to passages 344A, 344B andoutput vent passage 346. That is, in such a design, this valve has inputchamber 318 and guide pin 336 non-symmetrically arranged with respect tothe location of the plunger of actuator 80. The symmetrical andnon-symmetrical embodiments are equivalent.

FIG. 9B illustrates another embodiment of the “fram piston” valvedevice. Valve device 400 includes a valve body providing a cavity for avalve assembly 414, an input port 419, and an output port 421. Valveassembly 414 includes a proximal body 402, a distal body 404, and a frammember or assembly 426. Fram member 426 includes a pliable member 428and a support member 432. Pliable member 428 may be a diaphragm-likemember with sliding seal lips 429A and B. Support member 432 may beplunger-like member or a piston like member, but having differentstructural and functional properties than a conventional plunger orpiston. The valve body provides a guide surface 436 located on theinside wall that includes one or several grooves 438 and 438A. These arenovel grooves constructed to provide fluid passages from input chamberlocated peripherally (unlike the central input chamber shown in FIG. 9).

Fram member 426 defines a pilot chamber 442 arranged in fluidcommunication with actuator cavity 450 via control passages 444A and444B. Actuator cavity 450 is in fluid communication with output port 421via a control passage 446. Groove 438 (or grooves 438 and 438A) providesa communication passage between input port 419 and pilot chamber 442.Distal body 404 includes an annular lip seal 425 co-operatively arrangedwith pliable member 428 to provide a seal between input port 419 andoutput port 421. Distal body 404 also includes flow channel 417providing communication (in the open state) between input port 419 andoutput port 421 for a large amount of fluid flow. Pliable member 428also includes sliding seal lips 429A and 429B (or one sided sealingmember depending on the pressure conditions) arranged to provide asliding seal with respect to valve body 422, between pilot chamber 442and input port 419. (Of course, groove 438 enables a controlled flow offluid from input port 419 to pilot chamber 442, as described above.) Theentire operation of valve device 400 is controlled by a single solenoidactuator, such as the isolated actuator, 81.

FIGS. 10, 10A, 10B, and 10C illustrate several embodiments of theisolated actuator. Isolated actuator 80 includes solenoid windings 728wound about solenoid bobbin 714 and magnet 723 located in a magnetrecess 720. The actuator also includes a resiliently deformable O-ring712 that forms a seal between solenoid bobbin 714 and actuator base 716,and includes a resiliently deformable O-ring 730 that forms a sealbetween solenoid bobbin 714 and pole piece 725. All of these componentsare held together by a solenoid housing 718 (i.e., can 718), which iscrimped at actuator base 716 to hold magnet 723 and pole piece 725against bobbin 714 and thereby secure windings 728 and actuator base 716together.

Isolated actuator 81 also includes a resilient diaphragm membrane 764that may have various embodiments shown and described in connection withFIGS. 10D and 10E. As shown in FIG. 10, resilient diaphragm membrane 764is mounted between actuator base 716 and piloting button 705 to enclosearmature fluid located in a fluid-tight armature chamber incommunication with armature port 752. Resilient diaphragm membrane 764includes a distal end 766, O-ring like portion 767 and a flexibleportion 768. Distal end 766 comes in contact with the sealing surface inthe region 708. Resilient diaphragm membrane 764 is exposed to thepressure of regulated fluid provided via conduit 706 in piloting button705 and may therefore be subject to considerable external force.Furthermore, resilient diaphragm membrane 764 is constructed to have arelatively low permeability and high durability for thousands ofopenings and closings over many years of operation.

Referring to still to FIG. 10, isolated actuator 80 is provided, forstorage and shipping purposes, with a cap 703 sealed with respect to thedistal part of actuator base 716 and with respect to piloting button 705using a resiliently deformable O-ring 732. Storage and shipping cap 703includes usually water that counter-balances fluid contained byresilient diaphragm membrane 764; this significantly limits oreliminates diffusion of fluid through resilient diaphragm membrane 764.

Isolated actuator 81 may be constructed either as a latching actuator(shown in FIG. 10) or a non-latching actuator. The latching embodimentincludes magnet 723 (as shown) providing magnetic field havingorientation and force sufficient to overcome the force of coil spring748 and thereby retain armature 740 in the open state even after thereis no drive current flowing in the solenoid's windings 728.

In the non-latching embodiment, there is no permanent magnet (i.e., nomagnet 723). Thus, to keep armature 740 in the open state, a drivecurrent must continue to flow in windings 728 to provide the necessarymagnetic field. Armature 740 moves to the closed state under the forceof spring 748 if there is no drive current. On the other hand, in thelatching embodiment, a drive current is applied to windings 728 inopposite directions to move armature 740 between the open and closedstates, but no drive current is necessary to maintain either state.

Referring still to FIG. 10, actuator base 716 includes a wide baseportion substantially located inside can 718 and a narrowed baseextension threaded on its outer surface to receive cap 703. The innersurface of the base extension threadedly engages complementary threadsprovided on the outer surface of piloting button 705. Resilientdiaphragm membrane 764 includes a thickened peripheral rim 767 locatedbetween the base extension lower face and piloting button 705. Thiscreates a fluid-tight seal so that the membrane protects the armaturefrom exposure to external fluid flowing in the main valve.

For example, the armature liquid may be water mixed with a corrosioninhibitor, e.g., a 20% mixture of polypropylene glycol and potassiumphosphate. Alternatively, the armature fluid may include silicon-basedfluid, polypropylene polyethylene glycol or another fluid having a largemolecule. The armature liquid may in general be any substantiallynon-compressible liquid having low viscosity and preferablynon-corrosive properties with respect to the armature. Alternatively,the armature liquid may be Fomblin or other liquid having low vaporpressure (but preferably high molecular size to prevent diffusion).

If there is anticorrosive protection, the armature material can be alow-carbon steel, iron or any soft magnetic material; corrosionresistance is not as important a factor as it would otherwise be. Otherembodiments may employ armature materials such as the 420 or 430 seriesstainless steels. It is only necessary that the armature consistessentially of a ferromagnetic material, i.e., a material that thesolenoid and magnet can attract. Even so, it may include parts, such asa flexible or other tip, that is not ferromagnetic.

Resilient diaphragm membrane 764 encloses armature fluid located in afluid-tight armature chamber in communication with armature port 752 or790 formed by the armature body. Furthermore, resilient diaphragmmembrane 764 is exposed to the pressure of regulated fluid in the mainvalve and may therefore be subject to considerable external force.However, armature 740 and spring 748 do not have to overcome this force,because the conduit's pressure is transmitted through resilientdiaphragm membrane 764 to the incompressible armature fluid within thearmature chamber. The force that results from the pressure within thechamber therefore approximately balances the force that the conduitpressure exerts.

Referring still to FIGS. 10, 10A, 10B and 10C, armature 740 is free tomove with respect to fluid pressures within the chamber between theretracted and extended positions. Armature port 752 or 790 enables theforce-balancing fluid displaced from the armature chamber's lower wellthrough the spring cavity 750 to the part of the armature chamber fromwhich the armature's upper end (i.e. distal end) has been withdrawn uponactuation. Although armature fluid can also flow around the armature'ssides, arrangements in which rapid armature motion is required shouldhave a relatively low-flow-resistance path such as the one that port 752or 790 helps form. Similar considerations favor use of anarmature-chamber liquid that has relatively low viscosity. Therefore,the isolated operator (i.e., actuator 81) requires only low amounts ofelectrical energy for operation and is thus uniquely suitable forbattery operation.

In the latching embodiment shown in FIG. 10, armature 740 is held in theretracted position by magnet 723 in the absence of a solenoid current.To drive the armature to the extended position therefore requiresarmature current of such a direction and magnitude that the resultantmagnetic force counteracts that of the magnet by enough to allow thespring force to prevail. When it does so, the spring force movesarmature 740 to its extended position, in which it causes the membrane'sexterior surface to seal against the valve seat (e.g., the seat ofpiloting button 705). In this position, the armature is spaced enoughfrom the magnet that the spring force can keep the armature extendedwithout the solenoid's help.

To return the armature to the illustrated, retracted position andthereby permit fluid flow, current is driven through the solenoid in thedirection that causes the resultant magnetic field to reinforce that ofthe magnet. As was explained above, the force that magnet 723 exerts onthe armature in the retracted position is great enough to keep it thereagainst the spring force. However, in the non-latching embodiment thatdoesn't include magnet 723, armature 740 remains in the retractedposition only so long as the solenoid conducts enough current for theresultant magnetic force to exceed the spring force of spring 748.

Advantageously, resilient diaphragm membrane 764 protects armature 740and creates a cavity that is filled with a sufficiently non-corrosiveliquid, which in turn enables actuator designers to make more favorablechoices between materials with high corrosion resistance and highmagnetic permeability. Furthermore, diaphragm membrane 764 provides abarrier to metal ions and other debris that would tend to migrate intothe cavity.

Resilient diaphragm membrane 764 includes a distal sealing surface 766,which is related to the seat opening area, both of which can beincreased or decreased. The distal sealing surface 766 and the seatsurface of piloting button 705 can be optimized for a pressure range atwhich the valve actuator is designed to operate. Reducing distal sealingsurface 766 (and the corresponding tip of armature 740) reduces theplunger area involved in squeezing the membrane, and this in turnreduces the spring force required for a given upstream fluid-conduitpressure. On the other hand, making the plunger tip area too small tendsto damage resilient diaphragm membrane 764 during valve closing overtime. Preferable range of tip-contact area to seat-opening area isbetween 1.4 and 12.3. The present actuator is suitable for a variety ofpressures of the controlled fluid including pressures of about 150 psi.Without any substantial modification, the valve actuator may be used inthe range of about 30 psi to 80 psi, or even water pressures of about125 psi.

Referring still to FIGS. 10, 10A, 10B and 10C, piloting button 705 hasan important novel function for achieving consistent long-term pilotingof any solenoid valve. Solenoid actuator 81 together with pilotingbutton 705 are installed together as one assembly into the electronicfaucet; this minimizes the pilot-valve-stroke variability at the pilotseat in region 708 (FIGS. 10, 10B and 10C) with respect to the closingsurface (shown in detail in FIG. 10E), which variability would otherwiseaffect the piloting operation. This installation is faster and simplerthan prior art installations.

The assembly of operator 81 (or 81A, or 81B) and piloting button 705 isusually put together in a factory and is permanently connected therebyholding resilient diaphragm membrane 764 and the pressure loadedarmature fluid (at pressures comparable to the pressure of thecontrolled fluid). Piloting button 705 is coupled to the narrow end ofactuator base 716 using complementary threads or a sliding mechanism,both of which assure reproducible fixed distance between distal end 766of diaphragm membrane 764 and the sealing surface of piloting button705. The coupling of operator 80 and piloting button 705 can be madepermanent (or rigid) using glue, a set screw or pin. Alternatively, onemember may include an extending region that is used to crimp the twomembers together after screwing or sliding on piloting button 705.

It is possible to install solenoid actuator 81 (or 81A or 81B) withoutpiloting button 705, but this process is somewhat more cumbersome.Without piloting button 705, the installation process requires firstpositioning the pilot-valve body with respect to the main valve and thensecuring the actuator assembly onto the main valve as to hold thepilot-valve body in place. If proper care is not taken, there is somevariability in the position of the pilot body due to various piece-parttolerances and possible deformation. This variability createsvariability in the pilot-valve member's stroke. In a low-power pilotvalve, even relatively small variations can affect timing or possiblysealing force adversely and even prevent the pilot valve from opening orclosing at all. Thus, it is important to reduce this variability duringinstallation, field maintenance, or replacement. On the other hand, whenassembling solenoid actuator 81 (81A or 81B) with piloting button 705,this variability is eliminated or substantially reduced during themanufacturing process, and thus there is no need to take particular careduring field maintenance or replacement. In automatic valve 250,piloting button 705 is co-operatively constructed and arranged with thedesign of cavity 350 and sealing surface 348 to enable a novel way ofassembling a pilot-valve-operated valve 250.

Referring to FIGS. 10D and 10E, as described above, resilient diaphragmmembrane 764 includes an outer ring 767, flex region 768 and tip ordistal sealing region 766. The distal tip of the plunger is enclosedinside a pocket flange behind the distal sealing region 766. Preferably,diaphragm membrane 764 is made of EPDM due to its low durometer andcompression set by NSF part 61 and relatively low diffusion rates. Thelow diffusion rate is important to prevent the encapsulated armaturefluid from leaking out during transportation or installation process.Alternatively, resilient diaphragm membrane 764 can be made out of aflouro-elastomer, e.g., VITON, or a soft, low compression rubber, suchas CRI-LINE® flouro-elastomer made by CRI-TECH SP-508. Alternatively,diaphragm membrane 764 can be made out of a Teflon-type elastomer, orjust to include a Teflon coating. Alternatively, resilient diaphragmmembrane 764 can be made out of NBR (natural rubber) having a hardnessof 40-50 durometer as a means of reducing the influence of moldingprocess variation yielding flow marks that can form micro leaks of thecontained fluid into the surrounding environment. Alternatively,resilient membrane 764 can include a metallic coating that slows thediffusion through the diaphragm member when the other is dry and exposedto air during storage or shipping of the assembled actuator.

Preferably, resilient diaphragm membrane 764 has high elasticity and lowcompression (which is relatively difficult to achieve). Diaphragmmembrane 764 may have some parts made of a low durometer material (i.e.,parts 767 and 768) and other parts of high durometer material (frontsurface 766). The low compression of resilient diaphragm membrane 764 isimportant to minimize changes in the armature stroke over a long periodof operation. Thus, contact part 766 is made of high durometer material.The high elasticity is needed for easy flexing of resilient diaphragmmembrane 764 in regions 768. Furthermore, resilient membrane part 768 isrelatively thin so that the diaphragm can deflect, and the plunger canmove with very little force. This is important for long-term batteryoperation.

Referring to FIG. 1E, another embodiment of resilient diaphragm membrane764 can be made to include a forward slug cavity 772 (in addition to therear plunger cavity shaped to accommodate the plunger tip). The forwardslug cavity 772 is filled with a plastic or metal slug 774. The forwardsurface 770 including the surface of slug 774 is cooperatively arrangedwith the sealing surface of piloting button 705. Specifically, thesealing surface of piloting button 705 may include a pilot seat 709 madeof a different material with properties designed with respect to slug774. For example, pilot seat 709 can be made of a high durometermaterial. Therefore, during the sealing action, resilient and relativelyhard slug 774 comes in contact with a relatively soft pilot seat 709.This novel arrangement of resilient diaphragm membrane 764 and pilotingbutton 705 provides for a long term, highly reproducible sealing action.

Resilient diaphragm membrane 764 can be made by a two stage moldingprocess whereby the outer portion is molded of a softer material and theinner portion that is in contact with the pilot seat is molded of aharder elastomer or thermo-plastic material using an over moldingprocess. The forward facing insert 774 can be made of a hard injectionmolded plastic, such as acceptable co-polymer or a formed metal disc ofa non-corrosive non-magnetic material such as 300 series stainlesssteel. In this arrangement, pilot seat 709 is further modified such thatit contains geometry to retain pilot seat geometry made of a relativelyhigh durometer elastomer such as EPDM 0 durometer. By employing thisdesign that transfers the sealing surface compliant member onto thevalve seat of piloting button 705 (rather than diaphragm member 764),several key benefits are derived. There are substantial improvements inthe process related concerns of maintaining proper pilot seat geometryhaving no flow marks (that is a common phenomenon requiring carefulprocess controls and continual quality control vigilance). This designenables the use of an elastomeric member with a hardness that isoptimized for the application.

However, automatic valve device 250 may be used with other solenoidvalves such as the bistable solenoid model no. AXB724 available fromArichell Technologies Inc., West Newton, Mass. Alternatively, actuator80 may include a latching actuator (as described in U.S. Pat. No.6,293,516, which is incorporated by reference), a non-latching actuator(as described in U.S. Pat. No. 6,305,662, which is incorporated byreference), or an isolated operator 81 as shown in FIGS. 10 through 10Cor described in PCT Application PCT/US01/51098, which is incorporated byreference. In general, a number of solenoid valves may be used such asdescribed in U.S. Pat. No. 4,225,111. An alternative bistable solenoidis described in U.S. Pat. No. 5,883,557 or 5,599,003.

FIG. 11 schematically illustrates a fluid flow control subsystem for alatching actuator 81. The flow control system includes againmicrocontroller 814, sensor or power switch 818, and solenoid driver820. As shown in FIG. 10, latching actuator 81 includes at least onedrive coil 728 wound on a bobbin and an armature that preferably is madeof a permanent magnet. Microcontroller 814 provides control signals 815Aand 815B to power driver 820, which drives solenoid 728 for movingarmature 740. Solenoid driver 820 receives DC power from battery 824 andvoltage regulator 826 regulates the battery power to provide asubstantially constant voltage to current driver 820. Coil sensors 843Aand 843B pick up induced voltage signal due to movement of armature 740and provide this signal to a conditioning feedback loop that includespreamplifiers 845A, 845B and flow-pass filters 847A, 847B. That is, coilsensors 843A and 843B are used to monitor the armature position.

Microcontroller 814 is again designed for efficient power operation.Between actuations, microcontroller 814 goes automatically into a lowfrequency sleep mode and all other electronic elements (e.g., inputelement or sensor 818, power driver 820, voltage regulator or voltageboost 826) are powered down. Upon receiving an input signal from, forexample, a motion sensor, microcontroller 814 turns on a powerconsumption controller 819. Power consumption controller 819 powers upsignal conditioner that provides power to microcontroller 814.

Also referring to FIG. 10, to close the fluid passage 708,microcontroller 814 provides a CLOSE control signal 815A to solenoiddriver 820, which applies a drive voltage to the coil terminals.Provided by microcontroller 814, the CLOSE control signal 815A initiatesin solenoid driver 820 a drive voltage having a polarity that theresultant magnetic flux opposes the magnetic field provided by permanentmagnet 723. This breaks magnet 723's hold on armature 740 and allows thereturn spring 748 to displace valve member 740 toward valve seat 708. Inthe closed position, spring 748 keeps resilient diaphragm membrane 764pressed against the valve seat of piloting button 705. In the closedposition, there is an increased distance between the distal end ofarmature 740 and pole piece 725. Therefore, magnet 723 provides asmaller magnetic force on the armature 740 than the force provided byreturn spring 748.

To open the fluid passage, microcontroller 814 provides an OPEN controlsignal 815B (i.e., latch signal) to solenoid driver 820. The OPENcontrol signal 815B initiates in solenoid driver 820 a drive voltagehaving a polarity such that the resultant magnetic flux opposes theforce provided by bias spring 748. The resultant magnetic fluxreinforces the flux provided by permanent magnet 723 and overcomes theforce of spring 748. Permanent magnet 723 provides a force that is greatenough to hold armature 740 in the open position, against the force ofreturn spring 748, without any required magnetic force generated by coil728.

Referring to FIG. 11, microcontroller 814 discontinues current flow, byproper control signal 815A or 815B applied to solenoid driver 820, afterarmature 740 has reached the desired open or closed state. Pickup coils843A and 843B (or any sensor, in general) monitor the movement (orposition) of armature 740 and determine whether armature 740 has reachedits endpoint. Based on the coil sensor data from pickup coils 843A and843B (or the sensor), microcontroller 814 stops applying the coil drive,increases the coil drive, or reduces the coil drive.

To open the fluid passage, microcontroller 814 sends OPEN signal 815B topower driver 820, which provides a drive current to coil 842 in thedirection that will retract armature 740. At the same time, coils 843Aand 843B provide induced signals to the conditioning feedback loop,which includes a preamplifier and a low-pass filter. If the output of adifferentiator 849 indicates less than a selected threshold calibratedfor armature 740 reaching a selected position (e.g., half distancebetween the extended and retracted positions, or fully retractedposition, or another position), microcontroller 814 maintains OPENsignal 815B asserted. If no movement of armature 740 is detected,microcontroller 814 can apply a different level of OPEN signal 815B toincrease the drive current (up to several times the normal drivecurrent) provided by power driver 820. This way, the system can movearmature 740, which is stuck due to mineral deposits or other problems.

Microcontroller 814 can detect armature displacement (or even monitorarmature movement) using induced signals in coils 843A and 843B providedto the conditioning feedback loop. As the output from differentiator 849changes in response to the displacement of armature 740, microcontroller814 can apply a, different level of OPEN signal 815B, or can turn offOPEN signal 815B, which in turn directs power driver 820 to apply adifferent level of drive current. The result usually is that the drivecurrent is reduced, or the duration of the drive current is much shorterthan the time required to open the fluid passage under worst-caseconditions (that has to be used without an armature sensor). Therefore,the system of FIG. 8 saves considerable energy and thus extends the lifeof battery 824.

Advantageously, the arrangement of coil sensors 843A and 843B can detectlatching and unlatching movements of armature 740 with great precision.(However, a single coil sensor, or multiple coil sensors, or capacitivesensors may also be used to detect movement of armature 740.)Microcontroller 814 can direct a selected profile of the drive currentapplied by power driver 820. Various profiles may be stored inmicrocontroller 814 and may be actuated based on the fluid type, fluidpressure, fluid temperature, the time actuator 840 has been in operationsince installation or last maintenance, a battery level, input from anexternal sensor (e.g., a movement sensor or a presence sensor), or otherfactors.

Optionally, microcontroller 814 may include a communication interfacefor data transfer, for example, a serial port, a parallel port, a USBport, or a wireless communication interface (e.g., an RF interface). Thecommunication interface is used for downloading data to microcontroller814 (e.g., drive curve profiles, calibration data) or for reprogrammingmicrocontroller 814 to control a different type of actuation orcalculation.

Referring to FIG. 10, electromagnetic actuator 81 is connected in areverse flow arrangement when the water input is provided via passage706 of piloting button 705. Alternatively, electromagnetic actuator 81is connected in a forward flow arrangement when the water input isprovided via passage 710 of piloting button 705 and exits via passage706. In the forward flow arrangement, the plunger “faces directly” thepressure of the controlled fluid delivered by passage 710. That is, thecorresponding fluid force acts against spring 748. In both forward andreverse flow arrangements, the latch or unlatch times depend on thefluid pressure, but the actual latch time dependence is different. Inthe reverse flow arrangement, the latch time (i.e., time it takes toretract plunger 740) increases with the fluid pressure substantiallylinearly, as shown in FIG. 12B. On the other hand, in the forward flowarrangement, the latch time decreases with the fluid pressure. Based onthis latch time dependence, microcontroller 814 can calculate the actualwater pressure and thus control the water amount delivery.

FIG. 11A schematically illustrates a fluid flow control system foranother embodiment of the latching actuator. The flow control systemincludes again microcontroller 814, power consumption controller 819,solenoid driver 820 receiving power from a battery 824 or voltagebooster 826, and an indicator 828. Microcontroller 814 operates in bothsleep mode and operation mode, as described above. Microcontroller 814receives an input signal from an input element 818 (or any sensor) andprovides control signals 815A and 815B to current driver 820, whichdrives the solenoid of a latching valve actuator 81. Solenoid driver 820receives DC power from battery 824 and voltage regulator 826 regulatesthe battery power. A power monitor 872 monitors power signal deliveredto the drive coil of actuator 81 and provides a power monitoring signalto microcontroller 814 in a feedback arrangement having operationalamplifier 870. Microcontroller 814 and power consumption controller 819are designed for efficient power operation, as described above.

Also referring to FIG. 11A, to close the fluid passage, microcontroller814 provides a CLOSE control signal 815A to solenoid driver 820, whichapplies a drive voltage to the actuator terminals and thus drivescurrent through coil 728. Power monitor 872 may be a resistor connectedfor applied drive current to flow through (or a portion of the drivecurrent). Power monitor 872 may alternatively be a coil or anotherelement. The output from power monitor 872 is provided to thedifferentiator of signal conditioner 870. The differentiator is used todetermine a latch point, as shown in FIG. 12A.

Similarly, as described in connection with FIG. 11, to open the fluidpassage, microcontroller 814 sends CLOSE signal 815A or OPEN signal 815Bto valve driver 820, which provides a drive current to coil 728 in thedirection that will extend or retract armature 740 (and close or openpassage 708). At the same time, power monitor 872 provides a signal toopamp 870. Microcontroller 814 determines if armature 740 reached thedesired state using the power monitor signal. For example, if the outputof opamp 870 initially indicates no latch state for armature 740,microcontroller 814 maintains OPEN signal 815B, or applies a higherlevel of OPEN signal, as described above, to apply a higher drivecurrent. On the other hand, if armature 740 reached the desired state(e.g., latch state shown in FIG. 12 as point 662, and shown in FIG. 12Aas point 664), microcontroller 814 applies a lower level of OPEN signal815B, or turns off OPEN signal 815B. This usually reduces the durationof drive current or the level of the drive current as compared to thetime or current level required to open the fluid passage underworst-case conditions. Therefore, the system of FIG. 12A savesconsiderable energy and thus extends life of battery 824.

FIG. 12B shows the pressure dependence of the latch time in the reverseflow arrangement. The measured dependence shows increasing latch timewith increasing pressure. Based on curve 666, the microcontroller cancalculate the input water pressure at membrane 764. Specifically, afterthe solenoid of the actuator is activated, microcontroller 814 searchesfor the latching point 662 in FIG. 12 or point 664 in FIG. 12A. When thetimer reaches the latching point, microcontroller 814 deactivates thesolenoid. Based on the latch time, microcontroller 814 calculates thecorresponding water pressure, using stored calibration data. Based onthe water pressure and the size of the orifices, the controller directsthe irrigation system to deliver a known amount of water discharged bythe sprinkler (or another water delivery unit).

While the invention has been described with reference to the aboveembodiments, the present invention is by no means limited to theparticular constructions described and/or shown in the drawings. In anyadditional equivalent embodiment, any one of the above-describedelements may be replaced by one or more equivalent elements, orsimilarly any two or more of the above-described elements may bereplaced by one equivalent element.

The present invention also comprises any modifications or equivalentswithin the scope of the following claims.

1. A communication system for an irrigation system, comprising: anirrigation system including a central controller interfaced with acentral valve and a central communication unit, said central valveregulating water flow for irrigation from a water source; said centralcommunication unit being constructed to transmit communication signalsproviding irrigation information; a number of sprinkler unitsconstructed to irrigate a land area, each said sprinkler unit includinga local controller interfaced with a local valve for controlling waterflow to a sprinkler, and a local communication unit, said localcommunication unit being constructed to receive communication signalsfrom said central communication unit and provide received irrigationinformation to said local controller, said local controller beingconstructed to control operation of said local valve based on saidirrigation information.
 2. The communication system of claim 1, whereinsaid central communication unit is constructed to receive saidcommunication signals, and said local communication unit is constructedto transmit communication signals.
 3. The communication system of claim2, wherein said central communication unit and said local communicationunit are coupled to water conduits connected to said water source andare constructed to generate pressure waves transmitted through water insaid conduits.
 4. The communication system of claim 3, wherein saidcentral communication unit and said local communication unit include apressure sensor arranged to detect said pressure waves.
 5. Thecommunication system of claim 2, wherein said central communication unitand said local communication unit are coupled to water conduitsconnected to said water source and are constructed to generate pressurepulses transmitted through water in said conduits.
 6. The communicationsystem of claim 5, wherein said central communication unit and saidlocal communication unit include a pressure sensor arranged to detectsaid pressure pulses.
 7. The communication system of claim 2, whereinsaid central communication unit and said local communication unit arecoupled to water conduits connected to said water source and includeultrasound transducers arranged to introduce ultrasound waves into waterin said conduits, said ultrasound transducers being also arranged todetect ultrasound waves propagating in said water conduits.
 8. Thecommunication system of claim 2, wherein said central communication unitand said local communication unit include pressure sensors are coupledto water conduits connected to said water source and include valvesarranged to introduce pressure pulses into said water conduits byopening and closing actions that lower and increase water pressure, saidpressure sensors being arranged to detect said pressure pulsespropagating in said water conduits.
 9. The communication system of claim2, wherein said central communication unit and said local communicationunit are RF communication units each coupled to an antenna constructedto rise using water pressure.
 10. The communication system of claim 1,wherein said local communication units are powered by a battery.
 11. Thecommunication system of claim 1, wherein said local communication unitsare powered by a battery being re-charged by a self-contained powersupply unit.
 12. The communication system of claim 11, wherein saidself-contained power supply unit includes a solar element utilizing thephotovoltaic effect.
 13. The communication system of claim 11, whereinsaid self-contained power supply unit includes a miniature water turbineutilizing the water flow energy for generating and providing electricalpower to said battery.
 14. A communication method suitable for anirrigation system, comprising: providing an irrigation system includinga central controller interfaced with a central valve and a centralcommunication unit, providing a number of sprinkler units constructed toirrigate a land area, each said sprinkler unit including a localcontroller interfaced with a local valve for controlling water flow to asprinkler, and a local communication unit; transmitting communicationsignals carrying irrigation information; and receiving saidcommunication signals and providing received irrigation information tosaid local controller, said local controller being constructed tocontrol operation of said local valve based on said irrigationinformation.
 15. The communication method of claim 14, further includingtransmitting communication signals by said local communication unit, andincluding receiving said communication signals by said centralcommunication unit.
 16. The communication method of claim 15, whereinsaid transmitting and receiving includes generating pressure wavestransmitted through water in said conduits. 17-26. (canceled)
 27. Anelectrically operated valve for delivering water, comprising: a valvebody having a water inlet and a water outlet; a valve closure elementlocated within said valve body and constructed to move between an openstate enabling water flow from said inlet to said outlet and a closedstate preventing said water flow from said inlet to said outlet; anelectromagnetic actuator attached to move with said valve elementincluding a sealing member; and a pilot mechanism constructed to controlsaid movement of said valve element between said open state and saidclosed state based on a position of said sealing member.
 28. Theelectrically operated valve of claim 27 wherein said valve closureelement is a valve diaphragm.
 29. The electrically operated valve ofclaim 27 wherein said valve closure element is a valve piston. 30-31.(canceled)
 32. The electrically operated valve of claim 27, wherein saidvalve closure element includes a fram member and a sliding seal actingon a surface of a valve cavity inside said valve body for providing twopressure zones and being slidably movable within said valve cavity, saidfram member assembly being constructed to move to an open positionenabling water flow from said inlet to said outlet.
 33. The electricallyoperated valve of claim 32, wherein said two pressure zones include twochambers separated by said fram member and wherein a first pressure zoneincludes a pilot chamber.
 34. The electrically operated valve of claim32, wherein said sliding seal includes a one-sided seal.
 35. Theelectrically operated valve of claim 32, wherein said sliding sealincludes a two-sided seal.
 36. The electrically operated valve of claim33, wherein said actuator is constructed and arranged to releasepressure in said pilot chamber and thereby initiate movement of saidfram member to said open position.
 37. The electrically operated valveof claim 27, wherein said actuator includes a latching actuator.
 38. Theelectrically operated valve of claim 27, wherein said actuator includesa non-latching actuator.